The present invention relates to a polishing apparatus using ice particles which is suitable for polishing a surface of an article having a relatively low hardness such as a compound semiconductor, a crystalline block, etc.
FIG. 3 shows a typical example of conventional polishing apparatus for such purposes. In this conventional polishing apparatus, a major or large-diameter rotary plate 102 is rotatably mounted on a fixed support member 101, and a plurality (3 in the illustrated example) of minor or small-diameter rotary disks 103 are rotatably mounted on the major rotary plate 102. On each of the rotary disks 103, a plurality of articles 104 to be polished such as semiconductor wafers are disposed substantially in a circumferentially spaced apart relation and fixed thereto through appropriate fixing means (not shown) such as vacuum chucks and the like.
In operation, a top plate (not shown) is first disposed on the top surfaces of the articles to be polished with some kind of fine abrasive particles such as Al.sub.2 O.sub.3, SiO.sub.2, etc. being interposed therebetween. Then the major rotary plate 102 and the minor rotary disks 103 are rotated with respect each other and with respect to the fixed support plate 101 under the action of a certain drive means (not shown) while supplying thereto purified water as a lubricant.
With the conventional polishing apparatus as constructed above, however, if the hardness of the articles to be polished is relatively low as compared with that of the abrasive particles employed, there will be a problem that the surfaces of the articles being polished are damaged, impaired or marred due to the excessive abrasive action of the abrasive particles. In order to avoid such a problem, it is necessary to carefully choose an appropriate kind of abrasive which has hardness matching that of the articles being polished. The selection of such an abrasive suited to the hardness of the articles being polished is generally a troublesome task, and it is often difficult to find an appropriate abrasive.